People with Fetal Alcohol Syndrome (FAS) exhibit striking deficits in social behavior; these alterations in social behavior are independent of changes in intelligence and may be very damaging with respect to day-to-day functioning. The goal of this proposal is to use a model of FAS in which the rat is exposed to alcohol during development to investigate the mechanism by which alcohol alters social behaviors in the rat. The model that is used is novel and exposes rats to alcohol during all three trimester equivalents or, in other words, during both the prenatal and postnatal periods. The first set of experiments characterizes the model by comparing the effects of alcohol exposure during both the prenatal and postnatal period to exposure during the first half of the prenatal period alone, the second half of the prenatal period alone, and the postnatal period alone on activity, passive avoidance learning and spatial learning. After characterizing the model in the first year, the next two years examine the effect of alcohol exposure during development on social motivation. The second set of experiments focuses on the social motivation in an affiliative context. The experiments use distress vocalizations under different conditions of isolation, running speed to gain access to a conspecific after varying degrees of social deprivation, and social preference for conspecifics with different levels of aggressiveness. The third set of experiments examines social motivation in an aggressive context using the resident/intruder paradigm for both males and females; the motivation is varied by changing the context in which the aggression occurs. All of the experiments on social motivation use the additive factors technique to tease apart effects on motivation from effects on perception or the response mechanism; generally this technique examines the behavior under varying degrees of motivation and predicts that if groups differ in social motivation, then they will differ in how their behavior is altered by alterations in the level of social motivation. Female rats exposed to alcohol during development are predicted to have enhanced social motivation whereas male rats exposed to alcohol during development are predicted to have deceased social motivation.